A family member, who had been unable to contact O'Toole for two days, entered the apartment and found the man and woman unresponsive and called emergency responders, police say.

At about 11:11 a.m. Saturday, rescue units found the bodies of Vu and O'Toole in a bedroom in the 5400 block of Westbard Avenue in Bethesda, where the 38-year-old man lived. Police found two guns and a note. Paul Starks said Vu died of a gunshot wound and had another cutting wound.

Police have confirmed to ABC7 that Vu and O'Toole were in a relationship.Friends tell ABC7's Haley Harrison that Vu was a devout Catholic who sung in the choir at Our Lady of Vietnam Parish. They described Vu as a reserved woman and said they’re shocked at the crime.

A church friend said she'd seen Vu with O'Toole last week and believed Vu's family struggled with the couple's relationship.

“To be with an American is not really accepted. So I'm pretty sure that's what the mother is kind of regretting about, because she didn't allow it,” Nguyen Nguyen said on Sunday.

Vu, 35, lived in the 10900 block of New Hampshire Avenue in Silver Spring.

“Mostly this is a tragedy. Detectives are looking at the how and the what. not so much the why at this point,” Starks said.

On Friday, two people died in a separate incident, also an apparent murder-suicide in Chillum. Prince George's County Police say a man was found lying in the street next to a gun around 2:45 p.m. Friday in the 600 block of Ray Road.

Police found a woman dead of apparent gunshot wounds in a car nearby. Police say the man died later. Police say it appears the man shot the woman and detectives are investigating this as an apparent murder-suicide. The man and woman appear to have been in a relationship, according to police.